Flotation process for separation of silica and rhodonite



Patented Jan. 19, 1954 FLOTA'IlION PROCESS FOR SEPARATION. OF

SILICA AND RHODONITE Carl H. Schack, Salt Lake City, Utah, and Karl 0. Dean, Mexico City, Mexico, assignors to the United States of America as represented by the Solicitor of the Department of the Interior No Drawing. Application December 15, 1952,

I Serial No. 326,172

r 6 Claims. (01. 241-2o) r (Granted under Title 35, U. S. Code (1952),

I The invention described herein may be manufactured and used by or for the Government of the United States for governmental purposes without the payment to us of any royalty thereon in accordance with the provisions of the act '01 April 30, 1928 (Ch. 460, 45 Stat. L. 467) This invention relates to aprocess for the concentration of manganese ores, and, more particularly, to a froth flotation process for the separation of silica from rhodonite ores.

Manganese concentrates to be readily marketable should contain at least 33 per cent manganese. Rhodonite, a manganese silicate, in purest form contains a theoretical 42.4 per cent manganese, but, in the form in which it usually occurs in nature, contains a somewhat lower percentage. For example, the rhodonite content of a typical ore contained 38.1 per cent manganese. This ore also contained sulfides and silica mineralsas Well as the rhodonite and analyzed only about 20 per cent of manganese. This ore can be concentrated by sink and float procedure to 26.0 to 29.0 per centmanganese. Flotation of the contained sulfides from the manganese raises the concentration of the manganese to only about 30 per cent. .Accordingly, separation of some of the contained silica is necessary to achieve a satisfactory grade of manganese concentrate. from this material by use of known flotation methods have not resulted in production of a. satisfactory grade and satisfactory recovery of manganese values.

Accordingly, an object of this invention is to provide an improved flotation method for sep- 'aration of silica and rhodonite.

Another object of this invention is to provide a combination of reagents that allows a satisfactory separation of silica and rhodonite.

A further object of this invention is to provide a flotation process for separation of silica However, attempts to remove silica- .ceous minerals is well known procedure. resulting concentrate is then treated for silica removal by the process of this invention in its sec. 266) time permits using a such smaller amount of expensive cationic-type collector and a shorter period of flotation. The theory of the reactions whereby the improvement in separation is obtained by the use of sodium phosphate is not definitely known. Flotation is a complex art in which little is known of the mechanisms whereby the flotation reagents, often in complex combinations and in minute quantities, accomplish the selective separations. In the present instance, the tri-sodiu-m phosphate in combination with the other reagents either activates the silica minerals, quartz, etc., or it depresses the rhodonite. The action in either instance may be a chemical reaction, a physiochemical reaction, or a simple, or complex adsorption.

The rhodonite ore may be first ground to a suitable degree of fineness, although'the invention is not dependent upon any particular limits in this respect. Ores ground to 48 mesh, minus 65 mesh, and minus 100 mesh have been satisfactorily employed. I

If sulfides are present in the ground ore, they may first be floated by conventiona1 methods. Most rhodonite ores contain a variety of sulfide minerals including galena, sphalerite, and pyrite and several siliceous minerals, chiefly rhodonite. quartz, chalcedony and opal. The separation of these sulfide minerals by flotation from the sili- The entirety or it may be screened into two or more fractions with flotation of silica from each of these fractions. The ore may also be deslimed and only the sand fraction floated.

from rhodonite whereby a rhodonite concentrate containing very little free silica and a silica concentrate containing very little manganese are obtained.

These and related objects and'advantages of the invention hereinafter apparent as the encohols.

Any standard frothing agent, such as the higher alcohols, pine oil, cresylic acid, B-23 frother, or others having no adverse efiect on the selectivity of the collecting agents may be employed in the process. B'-23 is'a frothing agent composed of a mixture of high boiling point al- Likewise, any of a number of known cationic collecting agents for silica flotation may be employed. Of these collecting agents lauryl amine hydrochloride, known commercially as E. P. 487 is preferred. Flotation from a subsuing description proceeds are accomplished by this invention which comprises adding to a pulp of rhodonite-silica containing material a'suitable frothing agent, dextrine and tri-sodium phosphate, adjusting the pH to approximately 7.0, and floating on the silica from the rhodonite by staged additions of a suitable cationic reagent; '1 .Theuse of tri-sodium phosphate in the combination of flotation reagents used for flotation of silica from rhodonite greatly enhances the selectivity pf the silica flotation and at the same stantially neutral pulp is preferred; The pH may be adjusted by the addition of sulfuric acid to the normally alkaline pulp. To illustrate the importance of pH adjustment, a-test'run utilizing a cationic collector known commercially as Armac 12D (the acetate salt of dodecyl amine) and an alkaline pH of 8.4, the natural pH of the ore ground in the water available, didnot produce the favorable results of the invention.

The invention will bezfurther illustrated but is not intended to be limited by the following examples of practice.

2,0 v 3 I-TEXAMPLE 1 A lead-zinc-mangan-ese ore containing thev minerals galena, sphalerite, silica, and rhodonite primarily and assaying 26.5 per cent" manganese was ground in an iron ball mill in five 4-minute stages through IOU-mesh. The sulfides were 4 EXAMPLE. 'II

Essentially the same procedure was used in this second example as was used in Example I, with-"theexceptionthat ore was ground to only 5 -minus- '65 mesh and manganese content of the orewas-higher.

Table 2.-Reagent'consumptiomin pound per ton of ore Time, DeX- E. P. minutes 2-6 13-23 K-101 ousoi NazPO trim msoi 487 Bulksulfidesunnhs. 5 0.15 0.15 -05+210 silica cones- 1 7 /5 0.90 0. 50 0. 50 0.22 270 silica cones "7% 1. 00 50 40 floated by usingnormal sulfide reagents, namely: *TdbZe'ZA Z-6 xanthate (potassium pentasol amyl xanthate), K-101 (ammonium thiocyanate), B23 I I weight Assay, pistribu. frother, and CuSO1. The tails from this flotation Products percent P i 223 ga were" then removed from the cell and screened into a plus 270-mesh fraction and a minus 2-70- Bulk sulfides 6. 7 9. 5 2. 2 mesh fraction. These fractions were then floated 1-270 giO a 1 "5.0 0. 0 1.8 .270 10- 0.2 4.3 12.1 1.8 separately in a meehanlcal flotation machine at +270 siogNmg as 25:1 m approximately per centsollds. 13-23 was added +2701v1nmi1. 43.3 as. s 52.4 to the pulpas a stabilizing frother in the amount jgg g8 1 2&1 1 0.2 ..9.8 20.1 8.7 Of 0.056 pound per ton of ore, dextrine 1n the -270sio1-1 r0. 8. 3 31.3 8.8 amount of 0.80 pound per ton and trisodium I 5- v phosphate in the amount of 0.50 pound per ton 30 fle mte'd'head 100.0 20.50 100.0 were then mixed together in warm water and added'to the cell, pH was then corrected down- EXAMPLE III ward from the pH of 8.4 used for sulfide flotation to a pH of 7.3. Small staged amounts of E. R 487 cationic collector Were'then added to float the successive silicaconcentrates. With the exception of varying amounts-of reagents, the flotation of both the plus 270- and -the minus 270-mesh fractions was identical.

7 This example-is submitted'solely to show the difference in results obtained from a test run previous to the time Nas-POr was used in testing and which duplicates the test shown in Example. 1,. except for varying the reagents. Note should be taken'of the reduced amount of E. P. 487 needed-in the test where NasPO4 was used.

" Table 3.--R'eagent consumptioit m -poundper 1 ton of ore Time. E'P minutes B H280 487 0-1110 Bulk sulfides 5 0.15 '.0.;050 I 0.10 -100+270 SiOQcOm: 10 .050. .05- 0.40 0. 00 1.0 -210 S102 cone 10 .050- .05 a .40 .17 .50

-Reagent consumpt'ion"and test results are shown in the following tables.

Table:1.-Reagent consumption in pound per ton of-ore Time, .E minutes 24; B 2.; K 101 ousol NaaPO4 tune B330 487 Bulk sulfides... --s'- 0.15 +270'silica flotation- '7 0.80 0.40- 0.15 270 silica flotation.v 7% s... .1. 00 40 ---.15'

Table 1A Table 3A Assay, Distribu- 1 1 Wi 'ht Assay, Distribu- Weight, Products g percent t1on,ner- Products percent fig 12;} {E5 percent cent M11 Bulksulfldeconceutrate"-.-- 7.6 0.5 1 2,7 k +270 SiOzNo. 1 .0. 7 9.5 2.4 iggglgig 1 0. a +270'S10,N0.2.-- 4.7 11.3 2.0 .f- 13.1 +270SiO2N0.3- 14.4 10:9 2.8 i l te e 34.1 25. +270 MntaiL- ..s1.3 V 35.3 41. 4 1 2.6.4 .1

-'27'0'sio'1\j0. 13.0 28. 1 13.1 32.3, 210 270M :ta 1 v 14.6 33.6 18.4 Calculated 1100.11

20' 10 100.0 Calculatedhad-.. 100.0, 20.09 100.0 V 1 i 9n-9 th9- orfiminsteitamnles clearly illustrates the advantages to be gained by the use 7 ,were required to float the silica minerals from each of the two sized fractions and a total of 0.77 pound of collector (E. P. 487) was used per ton of ore treated. The combined manganese products, plus the minus 270-mesh Mn tail,

represented a recovery of 52 per cent of the manganese and assayed 33.3 per cent manganese.

Example I is an exact duplicate test of Example III, except that tri-sodium phosphate was used. In this test only 7 minutes were required to floateach of the two sized fractions and a total of only 0.30 pound of collector (E. R487) was used per ton of ore treated. At the same time a recovery of 59.8 per cent ofthe manganese was made in a product assaying 34.0 per cent manganese. Comparison of the data from the two examples show that the use of tri-sodium phosphate decreases the time needed to float the silica minerals, reduces the amount of collector needed to less than half, and at the same time, improves both the grade of the final product and the overall recovery of the manganese.

It will be appreciated from a reading of the foregoing specification that the invention herein described is susceptible of various changes and modifications without departing from the spirit and scope thereof.

, What is claimed is:

1. A process for the froth flotation of silica from rhodonite comprising adding to a pulp of rhodonite-silica containing material a frothing agent, dextrine, and tri-sodium phosphate, adjusting the pH of the pulp to about 7, and floating the silica from the rhodonite by addition of a cationic collecting agent. v

2. A process for the concentration of rhodonite 3. A process for the concentration-of rhodonite ores comprising grinding the ore, separating the- ,sulfides from the ground ore by froth flotation,

adding to a pulp of the resulting siliceous mineral concentrate a frothing agent, dextrine, and trisodium phosphate, adding sulfuric acid to neutralize the pulp, adding a cationic collecting agent to the pulp, and floating the silica from the rhodonite. 7

4. A process for the concentration of rhodonite ores comprising grinding the ore to at least past 48 mesh, separating the sulfides from the ground ore by froth flotation, separating the resulting siliceous mineral concentrate into at least two size fractions, adding to a pulp of each fraction a frothing agent, dextrine and trisodium phosphate, neutralizing the pulp with sulfuric acid, adding a cationic collecting agent to the neutralized pulp, and floating the silica from the rhodonite.

5. A process for the froth flotation of silica by froth flotation, preparing a pulp of the siliceous ores comprising grinding the ore, separating the sulfides from the siliceous minerals, adding to a pulp of the resulting siliceous mineral concenminerals, adding to the pulp a stabilizing frothing agent, dextrine, and a small amount of trisodium phosphate, adjusting the pH of the pulp to approximately 7 by addition oi sulfuric acid, and floating the silica from the rhodonite by additions of lauryl amine hydrochloride between flota- References Cited in the file of this patent U. S. Bureau of Mines Report of Investigations,

RI 3842, February 1946, and RI 445, April 1949.

(Copies available in Scientific Library.) 

1. A PROCESS FOR THE FROTH FLOTATION OF SILICA FROM RHODONITE COMPRISING ADDING TO A PULP OF RHODONITE-SILICA CONTAINING MATERIAL A FROTHING AGENT, DEXTRINE, AND TRI-SODIUM PHOSPHATE, ADJUSTING THE PH OF THE PULP TO ABOUT 7, AND FLOATING THE SILICA FROM THE RHODONITE BY ADDITION OF A CATIONIC COLLECTING AGENT. 